JPH07105081B2 - Magneto-optical disk device and information processing method thereof - Google Patents

Abstract

In a magnetic-optical disc memory system wherein header information items which include sector marks indicating initial positions of sectors, track Nos., and sector Nos. are previously provided on a magnetic-optical disc in the form of embossed pits and wherein data information items are written in the form of magnetic signals in data parts other than the header parts; detection means (8, 11, 13, 14) for the header part and detection means (8, 9, 10, 19) for the data part are disposed, and the operation of switching outputs from both the detection means is controlled in accordance with a timing based on the point of time at which a sector mark signal has been detected from the output of the header part detection means.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk device, and particularly when performing sector management of information, a header signal and a data signal are detected by separate photo-detecting means, and switching synthesis is performed. The present invention relates to a magneto-optical disk file device suitable for stabilizing the switching operation when performing.

[Background of the Invention]

An example of a magneto-optical information recording / reproducing apparatus for recording / erasing by the thermomagnetic effect and reproducing by the magneto-optical effect is proposed in Technical Report CPM83-53, pp13-19 of the Institute of Electronics and Communication Engineers. This device uses a medium in which data is recorded by a magnetization signal and address information is recorded by a phase signal of the concave and convex pits. However, regarding the reproduction signal detection system, the processing of both information, that is, the switching and combining method is not mentioned.

[Object of the Invention]

An object of the present invention is to switch the header information, which is given as phase information in the magneto-optical disk device, and the data information, which is given as magnetization information, by separate detecting means, and then switch and combine them to process them as a series of information. The operation timing is obtained from the header information detection side before entering the switching section, or the header information is always set to the side that passes through the switching circuit before entering the access operation, and after the access is completed, the sector information is set. At the timing from mark detection,
An object of the present invention is to provide a sector management system of information that can surely perform switching processing at the time of access by performing the switching operation.

[Outline of Invention]

The magneto-optical disk device of the present invention comprises an optical means for irradiating a recording medium with laser light, a first detecting means for detecting a change in the amount of laser light returning from the recording medium, and a laser returning from the recording medium. Second detecting means for detecting changes in the plane of polarization of light, switch means for receiving output signals of the first and second detecting means, and output from the first detecting means selectively output from the switch means. Common signal processing means for processing the signal and the output signal from the second detecting means, and mark detecting means for detecting a predetermined mark provided on the recording medium based on the output signal from the first detecting means. , Timing generating means for generating a timing signal based on the output signal of the mark detecting means to control the switch means.

Furthermore, the information processing method of the present invention irradiates a recording medium having a header area in which a header signal is formed by concave-convex pits and a data area in which a data signal is magneto-optically recorded, with laser light, and returns light. An information processing method for detecting and reproducing a signal, which comprises reproducing a header signal when detecting a header signal and a data signal respectively, switching both signals and inputting them to a common signal processing means to form a series of signals. After the above, the signal is switched at a timing based on the header signal so that the data signal is inputted to the signal processing means.

More specifically, the header portion of the magneto-optical disk is a concave-convex type. The reproduction of the header section detects a change in the amount of reflected light. The data part shall reproduce the direction of perpendicular magnetization by utilizing the magneto-optical effect. On the other hand, the apparatus side is provided with a detection system for reading the header section and a detection system for reading the data section separately, and the output signal from each detection system is selected by a switching circuit corresponding to the header area and the data area. Therefore, it is handled as a series of information. The switching circuit is activated by directly inputting the signal detected by the reading detection system of the header section to the sector mark detection circuit and starting the mark recognition.

Management information is provided in the header section as uneven pits for the purpose of managing the input and output of information in units of centers.
The header section is composed of a sector mark for recognizing that it is the beginning of a sector, a track number, a sector number, a clock synchronization signal, an error correction signal, etc., which indicate the address of the sector. On the other hand, the range of the data part is between the header area and the next header area. In the present invention, since the detection system for reading the header and the detection system for reading the data are separately provided, the levels of the signals of both are adjusted by some method, and one of them is selected depending on each area. It is necessary to select the signal from the detection system.

When different types of signals such as a phase signal and a magnetization signal are detected by separate detection systems and handled as a series of information, it is necessary to switch the two signals by some method and then combine them. As a control method of this switching operation, several methods as shown below are possible.

For example, an encoder signal (pattern) for rotation control on the disk is provided and this encoder signal is detected. If the number and position of encoder patterns are made to correspond to each sector on the disk, the header area and the data area are recognized by the timing from the edge of the encoder signal, and the detection signal from each separate photodetector is detected. The switch circuit can be operated to switch and synthesize. However, this method is strict under the conditions that the encoder pattern and the position of each sector are accurately associated, and that the operation of the timing generation circuit is performed stably without being affected by temperature characteristics, etc. is not.

As another method, a means for detecting a sector mark from a signal after a switch circuit for switching and combining and switching between a header area and a data area depending on the timing from this mark detection can be considered. This method is, so to speak, one's own switching operation at the timing of its own signal. Certainly, when a certain track is constantly reproduced, the switching operation is performed normally, but when the amount of light emitted to the disk increases, such as when recording or erasing, or when another track is accessed. In some cases, the sector mark and header signal cannot be detected, so if the switching switch is on the data area side without address information, if the above processing is performed, a signal for returning the switching switch to the header area side is obtained. Therefore, a malfunction occurs and the subsequent processing cannot be continued.

Therefore, in the present invention, the photodetection signal on the header detection side before entering the switching switch is directly input to the sector mark detection circuit, and the switching switch is operated according to the timing from the mark detection signal. Therefore, after the access to the other track is completed, even if the switch is on the data area side, the normal switching operation is surely restored, so that the above-mentioned drawback can be solved. As another method, when the access processing is started, the switching switch is forcibly set so that the photodetection signal on the header detection side passes, and then the access is performed, and when the target track is reached, the access is restarted. , The switching operation is performed corresponding to the header area and the data area. In that case, the sector mark can be detected after the switching circuit, and the processing can be normally continued even if the switching switch is operated according to the timing from the mark detection signal.

Example of Invention

The present invention will be described below with reference to examples. First, a first embodiment will be shown. FIG. 1 is a diagram showing a schematic configuration of a magneto-optical disk device according to the present invention, and is a diagram showing a part of a magneto-optical head for a magneto-optical disk and a signal detection / processing system. The light beam emitted from the semiconductor laser 1 is made into a parallel beam by the collimator lens 2, and the light intensity distribution of the cross section is converted into a circular beam by the triangular prism 3. After passing through the beam splitter 4, the light is narrowed down by a narrowing lens 5 as a minute spot on a disk 6 having a recording film (perpendicular magnetization film). The electromagnetic coil 7
It provides a magnetic field for erasing. Information is reproduced by detecting the Kerr rotation of the reflected light. The reflected light from the disk 6 passes through the aperture lens 5 again, is then reflected by the beam splitter 4, is further reflected by the beam splitter 8, and then passes through the analyzer 9 to pass through the lens and pass through the lens. Guided to the detector 10, the magnetization information and the header information are detected.

It is convenient to preliminarily provide the header information in the form of concave and convex pits when creating a disc. That is, the header information is information such as a sector mark for recognizing the start position of each sector, a clocking signal required for data decoding, a track number, and a sector number. Generally, the user does not need polarization. This is because the information does not exist.

The light transmitted through the beam splitter 8 is reflected by the beam splitter.
The light is branched at 11, and one is led to an autofocus control photodetector 12 and the other to a tracking control photodetector 13. For example,
The light reflected by the beam splitter 11 passes through an astigmatic difference optical system consisting of a spherical lens and a cylindrical lens, is partially shielded by a knife edge, and is guided to a photodetector 12 for defocus detection. The light transmitted through the general beam splitter 11 is guided to a two-division photodetector 13 for detecting a track shift via a spherical lens.

By the way, the signal received by the photodetector 13 is
It is a signal that is modulated according to the amount of reflected light from the.
That is, the header information provided on the disk 6 in the form of unevenness can be detected not only by the photodetector 10 but also by the photodetector 13. The signal light to the photodetector 13 has a merit that it is difficult to be affected by the retardation of the disk 6 and the polarization due to the magnetization distribution because it does not pass through the analyzer. Therefore, in reproducing the header information, it is better to use the signal on the photodetector 13 side. Of course, since the magnetization information detects the rotation of the polarization plane, the signal on the photodetector 10 side must be used.

The laser irradiation optical system, the magnetization signal detection system, the header signal detection system, and the electromagnetic coil constitute a magneto-optical head, and the magneto-optical head is moved in an arbitrary radial direction of the disk 6 by a feed motor (not shown) or the like. It is configured so that it can be moved to a position.

Here, some explanation will be added to the structure of the header information. FIG. 2 shows an example of the structure of header information. In order to carry out the present invention, it is not always necessary to have the configuration and order shown in FIG. 2, but it is convenient to provide only the sector mark at the sector head position. Further, the number of bits of each component may be arbitrary.

Now, a sector mark detecting circuit system, a signal branching to the detecting circuit system, and a processing method for switching synthesis of magnetization information and header information, which are the points of the present invention, will be described.

In FIG. 1, the signal received by the photodetector 13 for header signal detection is amplified to an appropriate level by an amplifier 14, and then a variable gain for the purpose of matching the level with the sector mark detection circuit 15 and the magnetization signal. It is branched to the amplifier 16. When the sector mark is recognized by the sector mark detection circuit 15, a timing generation circuit 17 for determining the range of the data section (range from the header section to the beginning of the next sector) causes a switching signal 18 between the header section and the data section. Is generated.
On the other hand, the magneto-optical signal (data signal) received by the magnetization signal detecting photodetector 10 is amplified by the amplifier 19 and then sent to the switch circuit 20 for switching between the header part and the data part. After this, it is processed by the level slice circuit 21 and sent as a digital signal to the processing system of the next stage.

The above is an example of the configuration for carrying out the present invention, but a little explanation will be added to the following timing generation circuit 17 and switch circuit 20. The sector mark detection circuit 15 is a well-known circuit and does not need to be modified in particular with respect to this embodiment, and therefore its explanation is omitted.

FIG. 3 shows an example of the switch circuit 20.
The signals amplified by the header signal-side amplifier 16 and the magnetization signal-side amplifier 19 are DC-cut by the capacitors 201 and 202, respectively, and are then set to the midpoint potential by the resistors 203, 204 and 205, 206.
After switching to a signal centered on V / 2, diode switch 2
Entered on 07,208. The diode switch is opened / closed by a digital level signal from the timing generation circuit 27.

When the signal from the timing generator 17 is at "L" level,
Inverter 209 turns on because the base of transistor switch 210 goes high and opens diode switch 207. On the other hand, since the base of the transistor switch 211 is at a low level, the diode switch 208 is closed. Therefore, only the header signal is sent to the next stage. On the contrary, when the signal from the timing generation circuit 17 is at "H" level, the diode switch 207 is closed and the diode switch 208 is opened, so that only the data signal is sent to the next stage. The signal selected by the diode switch is
After passing through the buffer circuit 212, it is sent to the level slice circuit 21. The buffer circuit 212 is intended to reduce the output impedance and to stably send a signal, and the emitter follower circuit is shown as an example, but other circuits having the same effect may be used.

In FIG. 3, the timing generation circuit 17 is responsive to the generation of the sector mark detection signal to define the range of the data portion with the counter. That is, by counting the number of constant clocks, for example, a "L" level digital gate signal is generated for a header section and an "H" level digital gate signal is generated for a data section. of course,
On the contrary, even if the "H" level is output in the header section and the "L" level is output in the data section, the switch circuit 20
The same operation can be performed by reversing the operation of.

FIG. 4 shows how the switching signal 18 generated by the timing generation circuit 17 and the header and data signals are switched.

Note that the switch circuit 20 shown in this embodiment shows a configuration example of the diode switches 207 and 208, but a high-speed analog switch may be used. However, the time required for switching is
It is necessary to select it in consideration of the data transfer rate. For example,
If the transfer speed is about several hundred kilobytes per second, the switching speed needs to be 100 nanoseconds or less. The selection of this switching time is determined experimentally,
The final decision will be made by checking the actual signal processing circuit.

Next, a second embodiment of the present invention will be described. FIG. 5 is a block diagram showing the processing after the photodetector.
The configuration before the photodetectors 10 and 13 in FIG. 1 is omitted because it is the same in this second embodiment.

In FIG. 5, the magnetization information of the data area received by the photodetector 10 is amplified by the amplifier 19. On the other hand, the photodetector 13
The phase information of the header area received at is amplified by the amplifier 14 and then level-adjusted with the magnetization information by the variable gain amplifier 16. Both signals are switch circuits.
After being selected at 20, one is processed by the level slice circuit 21 and digitized. The other is branched to the sector mark detection circuit 15. When the sector mark in the header is detected, the timing generation circuit 17 causes the gate signal 18 to switch between the header area and the data area.
Is output. On the other hand, since the access operation command is supposed to be issued from the host controller (control unit), the switch control circuit 22 always detects the light from the time when the access command signal 23 is issued to the end of the access operation. The signal from the device 13 side passes through the switch circuit 20, and the detection signal is input to the level slice circuit 21 and the sector mark detection circuit 15 in the subsequent stage. Then, when the access command signal 23 is stopped, the gate circuit 18 from the timing generation circuit 17 causes the switch circuit 20 to return to the operating state again. Here, a part which is not included in the first embodiment but is added to the second embodiment, that is, the access command signal 23, the gate signal 18, the switching signal 24, and the input / output signals of the switch circuit 20, is used as a timing chart. I will show you.

FIG. 6 is a time chart showing the operation of the second embodiment. In FIG. 6, when there is no access command 23, the signal is at "H" level. When the access command 23 is “H”, the gate signal 18 generates a signal of “L” level in the header area and “H” level in the data area by the timing circuit 17 from the sector mark detection signal, Normal switching operation is performed. Here, consider a case where the access command 23 is generated. At this time, the access command 23 is "H"
Changes from "L". At the same time, the switching signal 24 is forced to "L" regardless of the state of the gate signal 18.
Drop it on. Therefore, the switch circuit 20 is selected so that only the signal on the header section reading photodetector side always passes through the switch circuit 20. And the access operation ends,
When the first sector mark is detected after the access command 23 returns to "H" level, the normal switching operation before access is repeated again.

FIG. 7 is a diagram showing a configuration example of the switch control circuit 22. In FIG. 7, reference numeral 30 is a delay circuit using a counter or the like, and when the sector mark detection signal 25 is input,
The detection signal 31 delayed by the time up to the beginning of the data area following the header area is output. The delay detection signal
Since 31 is input to the reset (R) terminal of the flip-flop 33 via the inverter 32, the flip-flop 33
Output 34 is at "H" level. Therefore, when the sector mark is detected, the AND circuit 35
One input 34 of the
18 is output as it is as the switching signal 24.

If the access operation starts, the access command signal 23
Goes to the "L" level and is given to the trigger (T) input of the flip-flop 33 through the inverter 36. Since the D input and the set (S) input of the flip-flop 33 are pulled up to the "H" level (V _OH ), the output of the flip-flop 33 is changed to the "L" level by the rising of the T input. become. Therefore, even if the level of the gate signal 18 is "H" level, the switching signal 24 is forcibly set to "L" level, so that the signal on the header detection side passes through the switch circuit 20. Is set. When the sector mark detection signal 25 is detected after the access operation is completed, the normal switching operation corresponding to the header area and the data area is resumed. The flip-flop shown in this embodiment is
33 uses a D type flip flop,
Other types of flip flops are acceptable. Further, the inverters 32 and 36 are also to be inserted or not in consideration of the operation of the flip-flop to be used.

FIG. 8 shows the logic operation of the switch control circuit 22 of FIG. 7 corresponding to the above description.

〔The invention's effect〕

According to the present invention, the magneto-optical disk of the type in which the header section is provided on the disk in the form of the concave and convex pits, and the data section is recorded in the magnetization direction, the photodetector dedicated to the header section read When handling the photodetector of (1) with a magneto-optical disk file device provided separately, the timing of switching and combining the signals from both detectors is
By directly taking the signal from the photodetector for reading the header section directly, the reading operation of the header section is interrupted by an access operation, etc. It has the effect of enabling stable and reliable sector management.
Also, the switching timing is performed by the sector mark detected from the signal after the switching switch, but the switching switch is forcibly set so that the signal from the photodetector dedicated to reading the header section always passes during access. However, the same effect can be obtained by returning to the normal switching operation at the end of access.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the configuration of a magneto-optical disk device according to the present invention, FIG. 2 is a diagram showing an example of the information configuration of the header section, and FIG. 3 is a switching circuit of the header section and the data section. FIG. 4 is a configuration diagram, FIG. 4 is a diagram showing an input signal and an output signal to a switching circuit and a switching operation, FIG. 5 is a diagram showing a second embodiment of the present invention, FIG. 6 is a FIG. 7 is a time chart showing a signal switching / combining operation according to the configuration of FIG. 7, FIG. 7 is a diagram showing a configuration example of a switch control circuit, and FIG. 8 is a time chart showing the operation of FIG. 1 ... semiconductor laser, 6 ... disk, 9 ... analyzer,
10 ... Magnetization signal photodetector, 13 ... Header signal photodetector, 15 ... Sector mark detection circuit, 17 ... Timing generation circuit, 18 ... Switching signal, 20 ... Switch circuit, 20
7,208 …… Diode switch.

Claims (8)

[Claims] 1. An optical means for irradiating a recording medium with laser light, a first detecting means for detecting a change in the amount of laser light returning from the recording medium, and a polarization plane of the laser light returning from the recording medium. Detecting means for detecting a change in the signal, switch means to which the output signals of the first and second detecting means are inputted, and the first means selectively output from the switch means.
Common signal processing means for processing the output signal from the detecting means and the output signal from the second detecting means, and the predetermined signal provided on the recording medium based on the output signal from the first detecting means. And a timing generating means for generating a timing signal based on an output signal of the mark detecting means to control the switch means. 2. A magneto-optical disk apparatus according to claim 1, wherein said timing generating means generates timing signals of two levels to control said switch means. 3. The magneto-optical disk device according to claim 1, wherein said signal processing means has a level slice circuit. 4. The optical device according to claim 1, wherein a variable gain amplifier to which an output signal of said first detecting means is input is provided in the preceding stage of said switch circuit. Magnetic disk device. 5. The timing generating means has a terminal to which an access command signal is inputted, and when the access command signal is inputted, the output signal of the first detecting means is inputted to the signal processing means. 7. The magneto-optical disk device according to claim 1, wherein the switch means is forcibly controlled. 6. A recording medium having a header area in which a header signal is formed by concavo-convex pits and a data area in which a data signal is magneto-optically recorded is irradiated with laser light, and the returning light is detected to detect the signal. An information processing method for reproducing, by detecting the header signal and the data signal,
When switching both signals and inputting them to a common signal processing means to form a series of signals, after the reproduction of the header signal is finished, the data signal is inputted to the signal processing means so that An information processing method for switching signals at a timing based on the above. 7. The information processing method according to claim 6, wherein the header signal and the data signal are level-matched and then input to the common signal processing means. 8. The information processing method according to claim 6, wherein the header signal includes at least one of a sector mark, a clock synchronization signal, a track signal, and a sector signal.